I think that someone else have had this problem before, but I'll try to explain it anyway :
I chipped with a M2 1.30 a V5 PAL console (GH-015, don't remember the BIOS version). Works great for all EXCEPT PS2 CD-R ! Some CD-R media boots fine, and some not : I insert the CD-R, the PS2 seems to boot almost immediately (I think the laser lens is all right) but the screens remains black for 10-15 seconds, then appear the browser screen for half a second (with 'NO DATA' written) and then... RSOD. At one point, the PS2 stopped to boot any of the CD-R media I have here, so I changed the chip with another M2 1.30 and some media booted again. I havn't had the time to perform a test... changing the Messiah2 with a Magic3.1... I'm pretty sure it would work perfectly.
The lens was pretty good in reading DVD-R and CD-R burned with PSX games... The boot was pretty fast.
I think this is a issue of the M2 version 1.30... I'm not sure if it happen just with V5 or can happen with any version.
Anyone have had this problem ? The new 1.31 has solved it ?